This invention relates to a rotor of a micro motor, and more particularly to a rotor of a micro motor for an electronic timepiece.
In micro motor used in electronic timepieces, a permanent magnet is generally mounted on a rotor shaft which is surrounded by a stator. However, when the magnet is made of a material having a fragility such as a ferritic steel, it is necessary to avoid mounting the magnet directly on the rotor shaft because the magnet tends to crack or craze. Therefore, as shown in FIG. 1, a bush 2 provided with a flange is mounted around a rotor shaft 1, and a magnet 3 is loosely fitted around the outer periphery of the bush 2 and secured thereto by means of an adhesive.
However, the adhering operation is not carried out automatically but must be manually effected, so that mass productivity is low. Further, in particular, the rotor of a watch is so small that the adhesive for fixing the magnet to the bush frequently becomes stuck to a portion which is not desired to be adhered, thereby resulting in a decrease in accuracy of motor operation, an increase in the number of inferior goods and a decrease in the overall yield of productivity.